Tang Xin, Sepehri-Amin H, Terada N, Martin-Cid A, Kurniawan I, Kobayashi S, Kotani Y, Takeya H, Lai J, Matsushita Y, Ohkubo T, Miura Y, Nakamura T, Hono K
National Institute for Materials Science, Tsukuba, 305-0047, Japan.
International Center for Young Scientists, National Institute for Materials Science, Tsukuba, 305-0047, Japan.
Nat Commun. 2022 Mar 31;13(1):1817. doi: 10.1038/s41467-022-29340-2.
Magnetic refrigeration (MR) is a key technique for hydrogen liquefaction. Although the MR has ideally higher performance than the conventional gas compression technique around the hydrogen liquefaction temperature, the lack of MR materials with high magnetic entropy change in a wide temperature range required for the hydrogen liquefaction is a bottle-neck for practical applications of MR cooling systems. Here, we show a series of materials with a giant magnetocaloric effect (MCE) in magnetic entropy change (-∆S > 0.2 J cmK) in the Er(Ho)Co-based compounds, suitable for operation in the full temperature range required for hydrogen liquefaction (20-77 K). We also demonstrate that the giant MCE becomes reversible, enabling sustainable use of the MR materials, by eliminating the magneto-structural phase transition that leads to deterioration of the MCE. This discovery can lead to the application of Er(Ho)Co-based alloys for the hydrogen liquefaction using MR cooling technology for the future green fuel society.
磁制冷（MR）是氢气液化的一项关键技术。尽管在氢气液化温度附近，磁制冷理论上比传统气体压缩技术具有更高的性能，但缺乏在氢气液化所需的宽温度范围内具有高磁熵变的磁制冷材料是磁制冷系统实际应用的一个瓶颈。在此，我们展示了一系列在铒（钬）钴基化合物中具有巨大磁热效应（MCE）的材料，其磁熵变（-∆S > 0.2 J cmK），适用于氢气液化所需的全温度范围（20 - 77 K）。我们还证明，通过消除导致磁热效应恶化的磁结构相变，巨大磁热效应变得可逆，从而使磁制冷材料能够可持续使用。这一发现可能会促使铒（钬）钴基合金在未来绿色燃料社会中用于采用磁制冷技术的氢气液化。
